Incoming/Outgoing Servers??? How to set up?

After being forced to switch to the "new and improved" Yahoo mail, which infuriates me on a daily basis, I've decided to use Mozilla Thunderbird. I downloaded it, but have no idea how to list the incoming and outgoing servers so that I can get my mail and use the program. I'm fairly computer-savvy, but this has always flummoxed me, and Yahoo isn't forthcoming, no surprise there. I'm using FF 23 as my browser.

@BruceR I may be repeating this post, but I can find no evidence on this site that I actually hit the "Post" button. The settings seemed to be the answer that I'm looking for, but there's one big difference this time that didn't occur when I successfully installed Thunderbird on my computer in another state a few months ago (but didn't remember what how I did it). This time the setup Wizard didn't ask me for a password to my email account, and so it will not download my mail. And it seems that there's nowhere in the settings that allows me to enter it. I'm completely stymied. Is there a fix, or should I try uninstalling and reinstalling it? Thanks.

I'm at my wits' end with Thunderbird, which works perfectly on that other computer. Initially, I had added two different Yahoo mail accounts. Following your last direction, I attempted to send a test email to myself on both. The first one did ask for my password, and it sent the test email. The second did not, and didn't send the test. Frustrated, I removed Thunderbird, deleting it completely using RevoUninstaller, and reinstalled it. Wasn't happy to see both accounts still there, with all their settings. This time, the account that hadn't asked for the password did, indeed, ask for one when I tried to send another test email, but it wanted the one for the other account! There seems to be no way to enter my password for that second email account. And neither one is retrieving new mail from the server. Do I just give up?

I'd just dump it and set up an email account at GMail (Google Mail)
I have four (currently) email accounts at GMail and I set it up with O.E.6 on my Windows XP or Windows Mail on Windows 7, 8 or even 8.1.

It gets all my email, every three minutes and puts it all in one screen where I can quickly read it.

It's the simplest way to handle email that I've ever found, in all the years that email has existed.

I liked Yahoo a lot until this forced "upgrade." Now nothing works right. I do have some Gmail accounts, but don't like them. I got used to the folders on Yahoo and don't like the lack of organization on GMail. Also, especially in light of the recent publicity about lack of privacy, I think Google is even more invasive than Yahoo. But I appreciate your suggestion.

Gmail will protect you from the prying of others, but will read your email to support their advertising habit.
Yahoo will read your email to support their advertising & until they recently introduced secure connections, did not protect your email from others.

If you are still having a problem with TB and Yahoo, let me know & I'll try to link an inactive Yahoo account to my TB client.